The present invention relates generally to an instrument cassette, and more particularly, to an instrument cassette that is equipped with a stacking feature having physical dimensions which do not compromise functionality of the instrument cassette.
An instrument cassette is a container in which medical or dental instruments may be retained during a cleaning process and subsequent storage of the instruments. During cleaning, sterilization and subsequent storage, it is sometimes desirable to stack one instrument cassette on top of another instrument cassette for purposes of space conservation.
To facilitate stacking, certain instrument cassettes have been designed with stacking features. One example of an instrument cassette that includes a stacking feature is U.S. Pat. No. 5,384,103 which is issued to Miller. The Miller reference discloses an instrument tray which includes a base and cover. The cover has a circular aperture positioned at each corner of its rectangular top surface. The base includes a rectangular floor having four foot members affixed thereto. Each foot member is affixed to a corner of the rectangular floor. In use, the foot members of one instrument tray are positioned to extend through the corresponding apertures of an adjacent instrument tray thereby inhibiting sliding of adjacent trays relative to each other.
In addition, it is not uncommon for containers outside of the instrument cassette art to be provided with stacking features. For example, U.S. Pat. No. 5,125,511 issued to Chamberlin et al. discloses a blow molded box which is used for containing videocassettes therein. In particular, the blow molded box includes a base having a first stacking structure. The box further includes a cover having a second stacking structure which cooperates with the first stacking structure so as to inhibit relative movement between adjacent boxes.
While the above described designs do adequately inhibit adjacent containers from moving relative to one another, these designs possess certain drawbacks. For example, in the Miller reference, when an upper instrument tray is stacked on top of a lower instrument tray, all of the foot members which are attached to the upper instrument tray extend into the container space of the lower instrument tray thereby consuming some of the limited container space of the lower instrument tray. In addition, the foot members described in the Miller reference are configured to have sharp edges and protrude from the instrument tray such that they are likely to tear or punch a hole through a wrap positioned around the instrument tray. This is another drawback since wraps are commonly positioned around instrument trays to protect the instruments contained therein from contamination once they have been sterilized, and tearing or punching a hole through the wrap compromises this protection. Specifically, creating a hole or tear in the wrap allows contaminating substances (e.g. dust or dirt) to pass through the hole or tear and come into contact with the instruments contained within the instrument tray.
Moreover, the first and second stacking structures of the blow molded box described in the Chamberlin reference extend into the interior of the box thereby consuming valuable container space. Additionally, when two blow molded boxes which incorporate Chamberlin's design are stack one on top of the other, the gap defined between the upper box and the adjacent lower box would be extremely narrow. More specifically, the first stacking structure of the lower box and the second stacking structure of the upper box are configured so that only an extremely small distance would separate the top surface of the cover of the lower box from the bottom surface of the base of the upper box. Thus, it would not be desirable to incorporate Chamberlin's design into an instrument cassette since facilitating air flow between adjacent instrument cassettes is an important consideration during an instrument cleaning process such as sterilization with an autoclave machine.
What is needed therefore is an instrument cassette that is equipped with a stacking feature which has physical dimensions which do not compromise functionality of the instrument cassette.